Monitoring equipment

Abstract

Monitoring equipment comprising a part which defines a cavity, and input device to input fluid under pressure into the cavity. Mounting devices are provided on the part to enable an engine fuel injector valve or other fluid release device to be connected to the part and to release fluid from the cavity intermittently when the system is in use. Controls are connected to issue a triggering signal to the fluid release device to cause the latter to release fluid from the cavity. A pressure sensor is coupled to the cavity to provide a measure of the pressure within the cavity. The equipment further comprises pressure signal modifying device connected to receive signals from the pressure sensor and the controls and constructed to provide an output signal which is a measure of the pressure of fluid within the cavity at the time the controls issues such a triggering signal, while the effect of signals from the pressure sensor received by the modifying device on the output signal therefrom at other times is obviated.

I claim:  
     
       1. Monitoring equipment comprising a part which defines a cavity, input means to input fluid under pressure into the cavity, mounting means on the part to enable a fluid release device to be connected to the part and to release fluid from the cavity intermittently when the system is in use, control means connected to issue a triggering signal to the fluid release device to cause the latter to release fluid from the cavity, and a pressure sensor coupled to the cavity to provide a measure of the pressure within the cavity, wherein the equipment further comprises pressure signal modifying means connected to receive signals from the pressure sensor and the control means and constructed to provide an output signal which is a measure of the pressure of fluid within the cavity at the time the control means issues the triggering signal, whilst the effect of signals from the pressure sensor received by the modifying means on the output signal therefrom at other times is obviated. 
     
     
       2. Monitoring equipment according to  claim 1 , wherein the input means of the monitoring equipment include an adjustable flow regulator which serves to regulate the input of fluid under pressure into the cavity. 
     
     
       3. Monitoring equipment according to  claim 2 , wherein the adjustable flow regulator comprises fluid flow control means coupled to the pressure sensor so that the fluid flow control means effects an increase or a decrease to the flow of fluid into the cavity, thereby to maintain the pressure of the fluid therein at a desired operating pressure. 
     
     
       4. Monitoring equipment according to  claim 3 , wherein the flow control means comprises an hydraulic amplifier arranged to operate valve means of the flow control means so as to effect such increase or decrease. 
     
     
       5. Monitoring equipment according to  claim 3 , wherein the flow control means comprises a first movable member, transducer means which serves to provide a force which acts on and moves the first movable member in dependence upon magnitude of an input signal delivered to the flow control means, two inputs connected to deliver pressurised fluid to opposite sides respectively of the first movable member and to opposite sides respectively of a second movable member, and output means from which fluid flows after it has reached the first movable member, in such a manner that movement of the first movable member in a first direction increases the resistance to flow of fluid from one of the two inputs to the said output means, so that pressure of fluid from that input urges the said second movable member in a given direction, whilst movement of the first movable member in a second direction, opposite to the first, increases the resistance to flow of fluid from the other of the said two inputs to the said output means, so that pressure of fluid from that other input urges the said second movable member in another direction opposite to the said given direction, the flow control means further comprising balancing means to balance the movement of the second movable member against said force, and valve means which are opened to an extent which is dependent upon the position of the second movable member, whereby the extent to which the valve means is opened is dependent upon magnitude of the input signal, so that the latter effects such increase or decrease. 
     
     
       6. Monitoring equipment according to  claim 5 , wherein the pressurised fluid delivered by the said two inputs is the pressurised fluid from the said input means. 
     
     
       7. Monitoring equipment according to  claim 5 , wherein the balancing means comprise a spring. 
     
     
       8. Monitoring equipment according to  claim 5 , wherein valve means of the flow control means is a slide valve. 
     
     
       9. Monitoring equipment according to  claim 8 , wherein the slide valve is a spool valve. 
     
     
       10. Monitoring equipment according to  claim 1 , wherein the pressure signal modifying means provides the output signal continuously to the adjustable flow regulator by holding the value it has at the time the control means issues the triggering signal until the time the control means issues a next triggering signal.